<template>
  <div>
    <div ref="refdemo">refdemo</div>
    <input type="range" v-model="size" />
  </div>
</template>

<script>
  import { ref,watch } from 'vue'
  export default{
    setup(){
      const refdemo = ref(null)
      const size = ref(24)
      
        
      watch(size,(val)=>{
        refdemo.value.style.fontSize = val + 'px'
      })
      
      return{
        refdemo,
        size
      }
    }
  }
</script>

<style>
</style>
